The present invention relates to an image processing apparatus and an image processing method, and storage media thereof. More to particularly, this invention relates to an image processing apparatus and an image processing method, and storage media thereof in which image can be enlarged in the horizontal scanning direction and in the vertical scanning direction with arbitrary scale factor by rendering the scanning speed of the vertical scanning direction variable.
FIG. 1 is a configuration view showing a configuration example of a multi-gradation image reduction processor for reducing an image in the conventional scanner. An A/D converter 28 converts an analog signal supplied from a photoelectric conversion element into a digital multi-image data. A horizontal scanning thinned-out pulse generator 30 thins out one-pixel pulse 25 according to reduction factor to output as an output image transfer clock 24. A horizontal scanning enable signal generator 31 generates a horizontal scanning enable signal 33 for specifying effective pixel in the direction of horizontal scanning from both of a vertical scanning pulse 21 and the one-pixel pulse 25. A vertical scanning enable signal generator 32 thins out the vertical scanning pulse 21 according to reduction factor to output a vertical scanning enable signal.
FIG. 2 is a timing-chart showing the timing of signal of the conventional multi-gradation image reduction processor shown in FIG. 1. As shown in the timing-chart, the A/D converter 28 converts the image before reduction in every one-pixel into an output image 23 (output image 77 of FIG. 2) consisting of multi-gradation digital value. Subsequently, the horizontal scanning thinned-out pulse generator 30 thins-out the one-pixel pulse 25. The thinned-out pulse is taken to be the output image transfer clock 24 (thinned-out pulse 78 of FIG. 2) for next stage of image processing (for instance, processor for performing gamma correction or binarization). Whereby, this configuration realizes reduction of the image.
Further, formerly, the Japanese Patent Application Laid-Open No. SHO 59-229549 discloses method for providing scanner capable of obtaining enlarged image. Combination is performed between dilation in the horizontal scanning direction according to movement of zoom lens of optical system and dilation in the vertical scanning direction of alteration of movement speed of the carriage.
In such the method, when it is intended to obtain an enlarged image with arbitrary scale factor, it is necessary to equip a mechanical section for moving the zoom lens accurately according to required scale factor, and a mechanical section for altering continuously movement speed of the carriage.
However, when the movement speed of the carriage is to alter continuously in wide range, if the stepping motor is used, the pulse frequency is to alter continuously, thus there is the problem that a control circuit thereof becomes complicated.
Further, the stepping motor has large vibration. For instance, when the stepping motor is driven with pulse frequency of one/(integer number) or pulse frequency of (integer number) times greater of natural vibration number of the mechanical section, the mechanical section resonates, with the result that there is the problem of influencing bad influence to the image obtained.
In the Japanese Patent Application Laid-Open No. HEI 3-198470, in order to achieve these problems, the method for reducing the vibration is proposed. The method for reducing the vibration is that it is intended to reduce the range of the pulse frequency in such a way that it causes the drive system of the stepping motor to be altered according to the enlargement factor. However, in this method, it is necessary to alter the pulse frequency continuously in some degree of range, thus it is incapable of being avoided influence of resonance completely. Also, there is the defect that drive circuit thereof becomes complicated.
A device by which those problems are overcome and realization of low cost is achieved is used practically as the well known technique. The device is that the scale factor in the horizontal scanning direction is fixed, and also the movement speed of the carriage is fixed. In the device, the image data is stored in a semiconductor memory once, at the time of read-out, the pixel just before in the horizontal scanning direction is inserted and the line just before in the vertical scanning direction is inserted, thereby the enlarged image is realized.
However, there are problems to be solved as following:
The first problem is that for instance, as disclosed in the Japanese Patent Application Laid-Open No. SHO 59-229549, combination between the method according to movement of optical lens and the method according to alteration of movement speed of the carriage brings the device into complicated, thus it is difficult to constitute the device at the low cost.
Because high accurate mechanism is necessary for moving zoom lens, and speed of the motor for movement of the carriage should be controlled according to the scale factor (for instance, at the time of enlargement of 200%, motor speed is to reduce to 50% of the same scale of 100%, or at the time of 141%, motor speed is to reduce to 71% of the same scale of 100%), therefore the circuit for controlling motor becomes complicated. Further, in case of usage of the stepping motor for the sake of movement of the carriage in order to constitute the device cheaply, mechanism for suppressing vibration becomes necessary because the stepping motor is accompanied with large vibration. Furthermore, when carriage movement speed is variable over the wide range, vibration source occurs in various kinds of frequency elements, it becomes more difficult to suppress vibration.
The second problem is that the stepping motor becomes vibration source of various kinds of frequency elements although the method disclosed in the Japanese Patent Application Laid-Open No. HEI 3-198470 is executed in order to improve the first problem. Because even though the method of the Japanese Patent Application Laid-Open No. HEI 3-198470 is executed, it is necessary to render the pulse frequency variable continuously within some degree of the range.
The third problem is that the above described well known method brings picture quality into deteriorated at the time of enlargement. Because an enlargement processing in the multi-gradation image greatly enlarges the size of the image memory. For that reason, the image memory is compelled to realize by a binary image which is binarization-processed with the technique of the error diffusion and/or the dither method.
In view of the foregoing, it is an object of the present invention, in order to overcome the above-mentioned problems, to provide an image processing apparatus and an image processing method, and a storage media thereof which equips a scanner capable of enlarging of a multi-gradation image with arbitrary scale factor.
In accordance with a first aspect of the present invention, in order to achieve the above-mentioned object, there is provided an image processing apparatus which scans a manuscript in order to read-out an image of the manuscript comprising a storage means for storing an image data corresponding to one line in a horizontal scanning direction, a first generation means for generating prescribed reference pulse, a second generation means for generating a thinned-out pulse obtained in such a way that the reference pulse is thinned-out with a prescribed rate, a read-out means for reading-out the image data stored in the storage means according to either the reference pulse or the thinned-out pulse, an output means for outputting the image data read-out by the read-out means according to either the reference pulse or the thinned-out pulse, a first changeover means for changing to be supplied either one between the reference pulse and the thinned-out pulse to the read-out means a second changeover means for changing to be supplied either one between the reference pulse and the thinned-out pulse to the output means a control means for controlling scanning speed in vertical scanning direction according to scale factor in the vertical scanning direction, and a thinning-out means for thinning-out the image data stored in the storage means in every one line unit according to scale factor in the vertical scanning direction.
In accordance with a second aspect of the present invention, in the first aspect, there is provided an image processing apparatus, wherein the control means permits the scanning speed in the vertical scanning direction to be slow down to enlarge the image in the vertical scanning direction, on the other hand, the thinning-out means carries out a thinning-out of the image data enlarged by the control means in every line unit in order to reduce the image in the vertical scanning direction, thus enlarging the image with arbitrary scale factor.
In accordance with a third aspect of the present invention, in the first aspect, there is provided an image processing apparatus, wherein a scanning in the vertical scanning direction is carried out by a stepping motor being operated synchronized with prescribed reference clock, and said control means consists of a frequency demultiplier which divides down the reference clock.
In accordance with a fourth aspect of the present invention, in the first aspect, there is provided an image processing apparatus, wherein the scanning in the vertical scanning direction is carried out by a stepping motor being operated synchronized with prescribed reference clock, and the control means controls the stepping motor by the reference clock in such a way that the stepping motor rotates in every angle of xcex8/N degrees (N is the M-th power of 2 (two), M is 0 or arbitrary natural number) on the supposition that the angle of xcex8 is an angle which the stepping motor rotates in every one clock of the reference clock.
In accordance with a fifth aspect of the present invention, in the first aspect, there is provided an image processing apparatus, wherein the image processing apparatus further comprises a generation means for generating a signal to specify an effective pixel of the image data corresponding to one line stored in the storage means according to the scale factor in the horizontal scanning direction.
In accordance with a sixth aspect of the present invention, in the first aspect, there is provided an image processing apparatus, wherein the storage means is an FIFO memory which reads-out the image data stored therein in the stored order.
In accordance with a seventh aspect of the present invention, in the first aspect, there is provided an image processing apparatus, wherein the image data is an image data of multi-gradation, and the storage means stores therein the image data of multi-gradation.
In accordance with an eighth aspect of the present invention, there is provided an image processing method which scans a manuscript to read-out an image of the manuscript comprising the steps of, a storage step for storing an image data corresponding to one line in the horizontal scanning direction, a first generation step for generating prescribed reference pulse, a second generation step for generating a thinned-out pulse obtained in such a way that the reference pulse is thinned-out with a prescribed rate, a read-out step for reading-out the image data stored in the storage step according to either the reference pulse or the thinned-out pulse an output step for outputting the image data read-out in the read-out step according to either the reference pulse or the thinned-out pulse a first changeover step for changing reading-out of the image data in the read-out step according to which one between the reference pulse and the thinned-out pulse a second changeover step for changing output of the image data in the output step according to which one between the reference pulse and the thinned-out pulse a control step for controlling scanning speed in vertical scanning direction according to scale factor in the vertical scanning direction, and a thinning-out step for thinning-out the image data stored in the storage means at the storage step in every one line unit according to the scale factor in the vertical scanning direction.
In accordance with a ninth aspect of the present invention, there is provided a storage media for storing therein an image processing method as a program which is capable of being executed the image processing method that an image processing method which scans a manuscript to read-out an image of a manuscript comprising the steps of, a storage step for storing an image data corresponding to one line in the horizontal scanning direction, a first generation step for generating prescribed reference pulse, a second generation step for generating a thinned-out pulse obtained in such a way that the reference pulse is thinned-out with a prescribed rate, a read-out step for reading-out the image data stored in the storage step according to either the reference pulse or the thinned-out pulse, an output step for outputting the image data read-out in the read-out step according to either the reference pulse or the thinned-out pulse, a first changeover step for changing reading-out of the image data in the read-out step according to which one between the reference pulse and the thinned-out pulse, a second changeover step for changing output of the image data in the output step according to which one between the reference pulse and the thinned-out pulse, a control step for controlling scanning speed in vertical scanning direction according to scale factor in the vertical scanning direction, and a thinning-out step for thinning-out the image data stored in the storage means at the storage step in every one line unit according to the scale factor in the vertical scanning direction.
As described above, in the image processing apparatus and the image processing method, and the storage media thereof according to the present invention, the image data corresponding to one line in the horizontal direction is stored in the image processing apparatus, the image processing apparatus generates the prescribed reference pulse and the thinned-out pulse obtained in such a way that the reference pulse is thinned-out with prescribed rate. The stored image data is read-out according to either the reference pulse, then the read-out data is outputted according to either the reference pulse or the thinned-out pulse. The scanning speed in the vertical scanning direction is controlled according to the scale factor in the vertical scanning direction, and the stored image data is thinned-out in every one line unit according to the scale factor in the vertical scanning direction.
The above and further objects and novel features of the invention will be more fully understood from the following detailed description when the same is read in connection with the accompanying drawings. It should be expressly understood, however, that the drawings are for purpose of illustration only and are not intended as a definition of the limits of the invention.